1. Field of Invention
The present invention relates generally to hydraulic actuators, and more specifically, but not by way of limitation, to redundant hydraulic actuators in control systems that include hydraulic controls.
2. Description of Related Art
Hydraulic systems employ numerous hydraulic devices to perform various functions. For example, a subsea blowout preventer (BOP) may employ hydraulic devices in the form of a ram, an annular, a connector, and a failsafe valve function. In the case of a BOP, when a hydraulic device malfunctions, is no longer usable, or leaks, drilling operations must to be suspended so that maintenance on the hydraulic device can be performed. As a result of the suspension of drilling operations, significant loss in revenue and/or significant costs are incurred.